[Core] Add way to check if a signal has any connections

Added to `Object` and `Signal`

5 files changed, 29 insertions, 0 deletions

diff --git a/core/object/object.cpp b/core/object/object.cpp
index 2d9d468d38..b3a4ec6e2e 100644
--- a/core/object/object.cpp
+++ b/core/object/object.cpp
@@ -1457,6 +1457,24 @@ bool Object::is_connected(const StringName &p_signal, const Callable &p_callable
 	return s->slot_map.has(*p_callable.get_base_comparator());
 }
 
+bool Object::has_connections(const StringName &p_signal) const {
+	const SignalData *s = signal_map.getptr(p_signal);
+	if (!s) {
+		bool signal_is_valid = ClassDB::has_signal(get_class_name(), p_signal);
+		if (signal_is_valid) {
+			return false;
+		}
+
+		if (!script.is_null() && Ref<Script>(script)->has_script_signal(p_signal)) {
+			return false;
+		}
+
+		ERR_FAIL_V_MSG(false, "Nonexistent signal: " + p_signal + ".");
+	}
+
+	return !s->slot_map.is_empty();
+}
+
 void Object::disconnect(const StringName &p_signal, const Callable &p_callable) {
 	_disconnect(p_signal, p_callable);
 }
@@ -1697,6 +1715,7 @@ void Object::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("connect", "signal", "callable", "flags"), &Object::connect, DEFVAL(0));
 	ClassDB::bind_method(D_METHOD("disconnect", "signal", "callable"), &Object::disconnect);
 	ClassDB::bind_method(D_METHOD("is_connected", "signal", "callable"), &Object::is_connected);
+	ClassDB::bind_method(D_METHOD("has_connections", "signal"), &Object::has_connections);
 
 	ClassDB::bind_method(D_METHOD("set_block_signals", "enable"), &Object::set_block_signals);
 	ClassDB::bind_method(D_METHOD("is_blocking_signals"), &Object::is_blocking_signals);
diff --git a/core/object/object.h b/core/object/object.h
index 1274247d71..763e2974b9 100644
--- a/core/object/object.h
+++ b/core/object/object.h
@@ -932,6 +932,7 @@ public:
 	MTVIRTUAL Error connect(const StringName &p_signal, const Callable &p_callable, uint32_t p_flags = 0);
 	MTVIRTUAL void disconnect(const StringName &p_signal, const Callable &p_callable);
 	MTVIRTUAL bool is_connected(const StringName &p_signal, const Callable &p_callable) const;
+	MTVIRTUAL bool has_connections(const StringName &p_signal) const;
 
 	template <typename... VarArgs>
 	void call_deferred(const StringName &p_name, VarArgs... p_args) {
diff --git a/core/variant/callable.cpp b/core/variant/callable.cpp
index 9dff5c1e91..bb2d0313f6 100644
--- a/core/variant/callable.cpp
+++ b/core/variant/callable.cpp
@@ -545,6 +545,13 @@ bool Signal::is_connected(const Callable &p_callable) const {
 	return obj->is_connected(name, p_callable);
 }
 
+bool Signal::has_connections() const {
+	Object *obj = get_object();
+	ERR_FAIL_NULL_V(obj, false);
+
+	return obj->has_connections(name);
+}
+
 Array Signal::get_connections() const {
 	Object *obj = get_object();
 	if (!obj) {
diff --git a/core/variant/callable.h b/core/variant/callable.h
index 63757d9d6e..e3c940a0e5 100644
--- a/core/variant/callable.h
+++ b/core/variant/callable.h
@@ -192,6 +192,7 @@ public:
 	Error connect(const Callable &p_callable, uint32_t p_flags = 0);
 	void disconnect(const Callable &p_callable);
 	bool is_connected(const Callable &p_callable) const;
+	bool has_connections() const;
 
 	Array get_connections() const;
 	Signal(const Object *p_object, const StringName &p_name);
diff --git a/core/variant/variant_call.cpp b/core/variant/variant_call.cpp
index 178c0bc4ec..63fb5e8d94 100644
--- a/core/variant/variant_call.cpp
+++ b/core/variant/variant_call.cpp
@@ -2121,6 +2121,7 @@ static void _register_variant_builtin_methods_misc() {
 	bind_method(Signal, disconnect, sarray("callable"), varray());
 	bind_method(Signal, is_connected, sarray("callable"), varray());
 	bind_method(Signal, get_connections, sarray(), varray());
+	bind_method(Signal, has_connections, sarray(), varray());
 
 	bind_custom(Signal, emit, _VariantCall::func_Signal_emit, false, Variant);